a. Field of the Invention
This invention relates to vehicle brakes. In particular, the invention relates to a bracket assembly for mounting a brake assembly and a brake actuator that reduces mechanical stress within the bracket assembly as compared to conventional bracket assemblies.
b. Background Art
In a conventional drum brake, a brake drum rotates with a wheel or wheels proximate to one end of an axle. The drum defines a radially inner braking surface. A brake spider is disposed about the axle and a pair of brake shoes are pivotally mounted at one end to the brake spider. The opposite end of each brake shoe is engaged by an actuating member such as a cam to move the brake shoes between positions of engagement and disengagement with the braking surface of the brake drum. The cam is driven by a brake actuator acting on one end of a camshaft supporting the cam.
Referring to FIGS. 1-2, in one conventional drum brake, a bracket assembly 10 supports various components of a brake assembly 12 and a brake actuator 14 and positions them relative to one another. The bracket assembly 10 includes a tube 16 through which the camshaft 18 extends and mounting brackets 20, 22 welded to either end of the tube 16 and configured for coupling to the brake actuator 14 and a brake spider 24, respectively. Dynamic vertical loads placed on the bracket 20 supporting the brake actuator 14 cause stress at the weld between the bracket 22 and the tube 16. This stress can lead to fracture of the weld. In order to reduce the stress at the weld and potential failure of the weld, a support 26 must be installed between the vehicle axle 28 and the tube 16. Although this support 26 reduces stress at the weld between tube 16 and bracket 22, stress then becomes concentrated at the weld between tube 16 and bracket 20. In order to reduce stress on this weld, a gusset 30 must be installed between tube 16 and bracket 20. The addition of support 26 and gusset 30 increases the complexity of assembly and the cost of the braking system. In another configuration, a pair of gussets (not shown) may be installed between tube 16 and bracket 22. In this configuration, however, the weld between the tube 16 and bracket 22 is still located in a high stress area and subject to failure. Further, the configuration again increases the complexity of assembly and the cost of the braking system and may further require the support 26 and gusset 30 shown in FIGS. 1-2.
The inventors herein have recognized a need for a bracket assembly for mounting a brake assembly and a brake actuator that will minimize and/or eliminate one or more of the above-identified deficiencies.